1. Field of the Invention
The present invention relates to a battery pack formed by arranging a plurality of cell modules, and to a holding member attached to an outer periphery of each cell module.
Priority is claimed on Japanese Patent Application No. 2005-176226, filed Jun. 16, 2005, the content of which is incorporated herein by reference.
2. Description of the Related Art
A battery pack may be formed by stacking cylindrical cell modules in a frame in a zigzag form, where each cell module is formed by serially connecting a plurality of unit cells (see Reference Document 1: Japanese Unexamined Patent Application, First Publication No. 2003-308816). In the battery pack disclosed in Reference Document 1, holding members, each having a polygonal section, are attached to the outer periphery of each cell module at specific intervals along the axis of the cell module, and a plurality of the cell modules are stacked in a zigzag in a manner such that corresponding outer faces of the holding members of adjacent cell modules contact each other.
The above conventional holding member has a circular shape, and is attached to the cell module by making the cell module pass through the holding member. Therefore, in order to combine the cell module with the holding member without play, the holding member should be made of an elastic material and be attached to the cell module by using elastic deformation, which makes the attachment operation inconvenient. In addition, in this case, there is little flexibility in selection of the material for making the holding member.